The effect of genistein and daidzein on the solubilization of lipid membrane by detergent

Summary.

The study was carried out to estimate the effect of soybean isoflavones (genistein and daidzein) on the process of solubilization of lipid dipalmitoylphosphatidylcholine membrane (DPPC) in the presence of anionic detergent sodium dodecyl sulfate (SDS). Genistein and daidzein prevent DPPC membrane solubilization in the presence of SDS. Protection by daidzein is more effective than genistein and arises from the interaction between isoflavone and hydrophilic part of the membrane. Changing of the hydrophobic-hydrophylic balance in the membrane in the presence of SDS leads to complete bilayer solubilization (at genistein concentration 50 μM) or new detergent-resistance structures are observed (at genistein concentration 200 μM and daidzein 50-200 μM). Complete solubilization of those new structures requires much higher concentration of SDS, than those required to solubilize the membrane without isoflavones.